This invention relates to a combined vent and escape hatch assembly that is adapted for installation in the roof of a vehicle such as a transit bus or a school bus.
U.S. Pat. No. 4,021,073 granted to Donald L. Manning May 3, 1977 discloses a combined vent and escape hatch assembly for a vehicle roof in which a hatch cover over a roof opening has over hinge linkage connecting the hatch cover to the roof structure at two opposite sides. The hinge linkage accommodates tilting the hatch cover upwardly in either of two directions or elevating the entire hatch cover to vent the vehicle through the roof opening. The hinge linkage at one side includes provision for separating parts of the hinge linkage to permit swinging the hatch cover fully open to use the roof opening to escape from the interior of the vehicle.
The hatch cover disclosed in the Manning ""073 patent is tilted upwardly by manually applying sufficient upward force to the underside of the hatch cover in the mid area at one of the sides that has a hinge linkage so that the hatch cover pivots on the hinge linkage at the opposite side of the hatch cover. The hatch cover is tilted upwardly in the opposite direction by manually applying sufficient force to the underside of the hatch cover in the mid area at the opposite side. The entire hatch cover is elevated by manually applying sufficient force to the mid area of both sides that have hinge linkage connecting the hatch cover to the roof structure. The hatch cover is swung fully open by manually applying an upward force to a spring biased operating arm of a lever that is located near the one side that has separable hinge linkage connecting the hatch cover to the roof structure. The upward force moves the arm and lever separating the hinge linkage at the one side and then swings the hatch cover about the hinge linkage at the opposite side to the filly open position.
U.S. Pat. No. 4,964,673 granted to Ronald C. Lamparter Oct. 23, 1990 discloses an improved vehicle hatch mounting assembly that operates in substantially the same way.
The hatch covers disclosed in the above patents are satisfactory for their intended purpose and have enjoyed substantial commercial success, particularly in the case of the improved version in accordance with the Lamparter ""673 patent. However, newer busses, particularly newer transit busses tend to have lower floors, particularly in the forward area of the bus, to accommodate passengers with disabilities. The lower floors increase the roof height which makes manual operation of the hatch covers difficult in many instances.
This invention provides a motorized vent and escape hatch cover wherein the roof hatch cover can be tilted upward in either direction and elevated entirely with ease. The motorized vent and escape hatch has a mounting ring fastened to a vehicle roof around a hatch hole. A hatch cover is attached to the mounting ring by a first over center hinge linkage mechanism pivotally connecting one side of the hatch cover to the mounting ring and a second over center mechanism pivotally connecting an opposite side of the hatch cover to the mounting ring. Each over center hinge linkage mechanism has first and second lever members pivotally connected to the mounting ring at one end, first and second plungers that are connected to the respective first and second plungers at the opposite end and that extend into opposite ends of a tube that is connected to the hatch cover. A compression spring in the tube biases the first and second plungers away from each other.
Each over center hinge linkage mechanism is associated with a drive mechanism that pivots the first and second lever members toward or away from each other to raise or lower its side of the hatch cover with respect to the mounting ring. Each drive mechanism includes first and second gear housings attached to the mounting ring, first and second gear trains disposed inside the respective gear housings, first and second electric motors attached to the respective gear housings for driving the first and second gear trains, and first and second output shafts that are driven by the first and second gear trains driving and that extend out of the first and second gear housings respectively with the first and second lever members being keyed to the first and second output shafts respectively. The gear trains are compound gear trains that reduce speed and increase torque.